The exhaust gas from a power plant can be recovered and used as a raw
reaction material
Energy-saving CO2 capture technology with H2 gas is developed by
integrating the CO2 separation and conversion process

Date:
June 19, 2020
Source:
Japan Science and Technology Agency
Summary:
A research group developed a new technology that can drastically
conserve the energy used to capture CO2 from gases exhausted
from a concentrated source such as thermal power plants. With
this technology, namely H2 stripping regeneration technology,
combustion exhaust gas can be replaced by CO2/H2 gas at lower
temperatures than those used in conventional technology.



FULL STORY ==========================================================================
A research group at Nagoya University has developed a new technology that
can drastically conserve the energy used to capture carbon dioxide (CO2),
one of the greenhouse gases, from facilities such as thermal power plants.

Conventionally, a significant amount of energy (3 to 4 GJ/ton-CO2) or high temperatures exceeding 100 deg.C has been required to capture CO2 from
gases exhausted from a concentrated source, and there are expectations
of the development of CO2 capture technology that consumes less energy.


==========================================================================
The research group led by Assistant Professor Hiroshi Machida has
developed an unprecedented CO2 capture technology, namely H2 stripping regeneration technology, in which hydrogen (H2) gas is supplied to the regeneration tower (desorber)(2). It is indicated in this research that,
with the implementation of this new technology, combustion exhaust gas
can be replaced by CO2/H2 gas at lower temperatures (85 deg.C) than those
used in conventional technology. The further reduction of energy can be achieved when it is combined with technologies such as those involved in
the promotion of exhaust heat utilization and recovery of reaction heat.

This new technology can exhibit the world's highest energy-saving
performance (i.e., separation and collection of energy required is less
than 1 GJ/ton-CO2 when a desorber temperature is 60 deg.C) when it is
combined with the phase- separation solvent that this research group
has also developed.

This technology is expected to be applicable to value-added material
production such as the syntheses of methane, methanol, gasoline, etc.,
from CO2 in the combustion exhaust gas and H2 from renewable energy,
and is expected to contribute to carbon recycling.

1) H2 stripping regeneration technology In the conventional process
to synthesize fuel or chemicals from CO2 and renewable H2, pure CO2
is collected and is then mixed with H2 before being supplied to the
reduction reactor. In the H2 stripping regeneration technology, H2 gas is supplied at the bottom of the desorber. As a result, CO2 partial pressure
in the desorber is lowered, which promotes regeneration and lowers the regeneration temperature. The mixture of CO2 and H2 gases collected from
the head of the desorber is supplied directly to the synthesis reactor.

2) Regeneration tower (Desorber) In the amine absorption method,
CO2 absorption and regeneration towers (i.e., absorber and desorber)
are used to separate and collect CO2 in the exhaust gas mixture from
facilities like power plants. Gases such as N2 and O2, in addition to
CO2, are included in the combustion exhaust gas from these facilities
and pure CO2 gas is collected with this amine absorption method. Only
the CO2 gas is absorbed in the absorber by amine solution, and it is
then heated in the desorber to regenerate pure CO2 gas. In other words,
only CO2 gas can be extracted from the mixture of gases.

This study has been supported by Advanced Low Carbon Technology Research
and Development Program (ALCA ) of JST Strategic Basic Research Programs.


========================================================================== Story Source: Materials provided by
Japan_Science_and_Technology_Agency. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Hiroshi Machida, Takehiro Esaki, Tsuyoshi Yamaguchi, Koyo Norinaga.

Energy-Saving CO2 Capture by H2 Gas Stripping for Integrating CO2
Separation and Conversion Processes. ACS Sustainable Chemistry &
Engineering, 2020; 8 (23): 8732 DOI: 10.1021/acssuschemeng.0c02459 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200619094207.htm

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